Some users have experienced this error: ‘Crashplan unable to connect to central.crashplan.com 443, check your network’ when attempting to log into their Crashplan account from the dashboard, usually just after the installation has completed.
There are a number of common issues – namely that a firewall is blocking the connection. View these articles as the solution to test whether the connection to Crashplan is indeed blocked. This can be done by using Telnet.
While these support pages may solve your problem, we have found they do not always provide a solution. One solution that we discovered was to simply add the crashplan security certificate to Internet Explorer.
Until we did this, no matter what we tried we were unable to make the connection – we tried re-starting the Crashplan service, uninstalling the software… the list goes on.
To install the certificate, log onto the Crashplan account page > View the website’s certificate > Install the certificate.